Our company's sales have shown significant fluctuation in recent months.

fluctuation 是名词，来自动词 fluctuate（波动、起伏）。fluctuate 由词根 fluct-（流动、波动）和后缀 -ate（使...）组成，字面意思是"使流动/波动"。fluctuation 指"波动、起伏"的状态或现象。